Tuesday, July 08, 2008

To power Cadel's hopes for winning this year's Tour, Ridley is unleashing a gamut of aerodynamic technologies in their latest TT bike, the Dean.

According to Ridley, the most disruption of airflow in conventional bicycles is concentrated near the fork and the rotating spokes of the front wheel.

Slotted airfoils, gimmicks used in the aerospace industry to create more lift with lower drag and consequently lower power input, are now used in this bike on the fork and seat stays to convert as many disruptive flows as one can get to a more uniform laminar as possible, without compromising structural integrity through other redesign schemes.

What is interesting though is another feature they are calling boundary layer technology. First if you're a tech head, read this material about boundary layer theory.

Now, from Ridley's own site, an excerpt on textured surfaces :

Ridley’s Aero line will also incorporate their proprietary boundary layer technology or R Surface™. The boundary layer is thin band of air that “adheres” to the surface of an airfoil. A thin boundary layer allows the air mass to travel around the frame smoothly. Using data from extensive wind tunnel testing during the painting process, Ridley engineers applied texture to strategic locations on the frame. Air moving over the textured surface becomes excited, which causes it to travel smoothly around the frame instead of detaching, creating speed-sapping drag. The use of R-Surface™ on the new Dean and Noah makes Ridley the first company in the bicycle industry to use this aerodynamic technology.

The Sydney Morning Herald says : Evans will ride a custom-made Ridley time-trial bike that has been developed around his build, position and style. The bike, named the Ridley "Dean", has been two years in the making and results from tests show it saves 15 watts of energy when it is ridden at 45kmh. Evans will follow a minute-by-minute schedule after he wakes and prepares for the time trial.

Ridley, what we're all really wondering is : Can this bike beat Koga Miyata's Million Dollar bike?! Someone touted that as the fastest bike in the world, now we're all sitting here confused about which one to buy - spend a million dollars for Koga or spend 4000 bucks on your frame. Its a really tough decision.

Second. I actually have worked in a wind tunnel where we studied the effects mentioned in this post. I have a M.S. in engineering with a focus in experimental fluid mechanics. The stuff they are talking about on the bike is true, it works, its crazy cool to study, but very tempermental. Finger prints can affect the airflow.

I would say the airfoils on the forks work, but the boundary layer technology I have not seen on a bike yet so I am not quite sold on that yet. In theory and experience it works, but I have only seen it in a wind tunnel, and the tour de france is not a wind tunnel. (I sure would love to work on that project)

My experienced revolved around the aerospace industry and largely the transonic region of the airfoil airflow. I did see the results on a gun turret experiment at low mach numbers M=0.1 to 0.2 with impressive results. So most of the articles and information I had only loosely corolate to the method. (same methodology different flow fields).

www.aiaa.org has a publication search. http://www.aiaa.org/content.cfm?pageid=413&reseta=1&versionid=533

search the word "bumps" and you will get some serious engineering articles.

Thats the best i can do, there aren't a lot of unclassified or proprietary documents in the open realm.

Hello, the real effect of the flying golf balls is the surface - bigger surface with dimples - according to aerodynamics the longer surface - quicker air speed - better aerodynamics. If you need best aerodynamics of your cycle please contact.